There are a large number of types of shelf-units currently used in self-service stores and these shelf-units differ from one another, especially as regards their dimensions, in particular their width and thickness. Owing to these differences, when it is desired to hook decoration, information or valorization elements, it is necessary to use a hooking device particularly adapted to the dimensions of the shelf-unit in question, this adaptation constituting a complication in that a complete range of hooking devices need to be retained, each hooking device being adapted to a particular type of shelf-unit.